Miniature electronic equipment is often portable in nature, and, as such, requires a portable source of power such as a battery. A battery supply may be conveniently attached to the housing of the miniature electronic equipment and make electronic contact by way of a conventional connector. To make battery changing easier, mechanisms have been devised to enable the user to easily disconnect the spent battery and replace it with a freshly charged battery. It has been proven desirable to securely affix the detachable battery to the miniature electronic equipment by way of a sliding channel and latching mechanism. As the equipment becomes smaller, however, it has become increasingly difficult to control the dimensions of the features critical to the interface between the battery and the electronic equipment. Critical interface features include the sliding channels, latch and battery contacts.
Typically, battery housings are assemblies having a housing base and a housing cover which are joined to each other to encompass electrochemical cells contained within the assembly. The sliding channel features are often designed into the battery housing assembly as a combination of features in the housing base and the housing cover. Variation in the assembly process attaching the base to the cover sometimes results in variation in the dimensions of the sliding channels. Variation in the dimensions of the sliding channels causes the position of the latch and battery contacts on the battery housing to vary relative to the slides. As a result, the battery may not fit or function properly when attached to the electronic equipment. Thus, it would be advantageous to manufacture all the critical interface features as part of the base so that their dimensions relative to each other may be controlled.
The difficulty in manufacturing all the critical interface features in the battery housing base arises in creating the guide rails for the sliding channels. The sliding channel usually has three inside surfaces forming a "U" shape. The guide rails are usually elongated protrusions disposed at intervals on one of the two parallel side surfaces inside the channel. The bottom surface of the channel is usually disposed perpendicularly to the two side surfaces. The guide rails are parallel to the bottom surface. Using conventional molding processes, the sliding channels, latch and battery contact receptacles are molded into the battery housing base anticipating a straight pull ejection from the tooling cavity. The guide rails in the sliding channels, however, are position perpendicularly to the direction of ejection from the tooling cavity.
One approach that has been considered involves insert molding. Using this process, the sides of the sliding channels including the guide rails are molded separately first then inserted into a second mold which forms the remaining two sides of the sliding channel and the complete molded battery housing base. The problem with this approach is that it is both labor and time intensive to complete the two stage molding process.
Another approach which has been considered involves comolding. Using this process, the side of the sliding channels including the guide rails are molded separately in a first cycle. One part of the tool is removed and replaced with a second part which has the remaining features of the sliding channel and the complete battery housing base. A second mold cycle is initiated to produce the completed battery housing base. The problem with this approach is that there are no automated comolding tools available which mold the first stage in a straight pull direction and the second stage in a pull direction perpendicularly to the first stage pull. Developing a specialized comolding process for a battery housing base would be expensive.
Thus, there is a strong need for a battery housing base with an integral, limited travel, sliding channel mechanism having guide rails which can easily be manufactured, has controlled critical interface dimensions and has its critical interface dimensions disassociated from the attachment of a battery housing cover.